Hermetically sealed triboelectric generator and impact sensing unit for a fuze



Sept. 23, 1958 7' R. BIRNCHI 2,853,009 l-IERNETICAILYSEALED BOELECTRIC GENERATOR AND IIIPACT SENSI UNIT FOR A FUZE Filed May 6. 1952 INVENTOR. R. BIANCHI m; um.

ATTYIS United States Patent HERMETICALLY SEALED TRIBOELECTRIC GEN- ?{EQEOR AND IMPACT SENSING UNIT FOR A Renato Bianchi, Laurel Md. assignor to the United States 3% America as represented by the Secretary of the This invention relates to an electric controlled projectile fuze and more particularly to a generating device for use in the base or nose of the fuze for generating electrical energy during the free flight of the projectile toward a target suflicient to function the fuze and explode the projectile upon impact of the projectile with a target.

The development of electric fuzes for projectiles, especially those employing electrically operated devices, has heretofore been impeded by lack of a satisfactory source of electric operating current to function the electrical devices therein particularly after the projectile has been stored over a long period of time under adverse weather conditions.

The present invention provides means wherebyan adequate source of current is developed within the projectile during the free flight of the projectile toward the target and thus assuring proper functioning of the device and explosion of the projectile upon impact of the projectile with a target notwithstanding the fact that the projectile may have been stored over a long period of time under adverse weather conditions. Furthermore, the present invention provides a device for use in an electric fuze having the essential characteristics of safety during handling and transportation and which is suficiently small in size such that the device may be used in the type of projectiles now used by the armed forces without increasing the normal size or weight of such projectiles.

The present invention contemplates the use of a new and improved generating device for a fuze which is in the form of a triboelectric or dust type electrostatic generator and in which means controlled by the spin of the projectile charges a storage device at a slow rate with electrical energy as the projectile travels along a trajectory and in which means are provided for causing the spin controlled means to discharge the energy instantaneously from the storage device through an electroresponsive detonator upon impact of the projectile with the target and in an amount suflicient to cause the detonator to be fired in response thereto and thus explode the projectile.

An object of the invention is the provision of a new and improved generating device for use in a projectile for generating electrical energy in response to rotation of the projectile during the free flight of the projectile toward a target.

Another object is the provision of a generator device in which means are provided for transferring the energy generated therein through an electroresponsive detonator to a storage device at a rate insufiicient to fire the detonator.

Another object is to provide a hermetically sealed dust type generating device in which means are provided for charging a storage device at a slow rate in one direction as the projectile spins along its trajectory and in which means are provided for causing the storage device to discharge instantaneously in the reverse direction at a rate sufficient to fire an electroresponsive detonator upon impact of the projectile with a target.

A further object of the invention is to provide ,a new and improved electric fuze for a projectile in which means are provided for delaying the arming of the fuze until the projectile has been fired from a gun and the speed of rotation of the projectile after being fired therefrom has reached a predetermined value.

An additional object resides in the provision of a dust type electrostatic generator for a projectile fuze which also functions as an impact responsive switch for controlling firingof the fuze.

Still another object is to provide a dust type electrostatic generator for a projectile fuze having provisions for releasing the dust particles in response to predetermined forces attendant upon the firing of the projectile from the gunand having additional provisions for new and im' proved distribution and centrifugal displacement of the alps: particles in response to the spin of the projectile in Other objects and many of the attended advantages of this invention will be readily appreciated as the same becomes betterunderstood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

Fig. l is a central longitudinal sectional view of the device of the present invention according to a preferred embodiment thereof;

Fig. 2 is a diagrammatic representation of an electrical circuit employed with the device of Fig. 1;

Fig. 3 is a central longitudinal sectional view of an alternate arrangement of the device of Fig. 1;

Fig. 4 is a diagrammatic representation of an electrical circuit employed with the device of Fig. 3; and

Fig. 5 is a central longitudinal sectional view of another arrangement of the device of Fig. 1.

Referring now to the accompanying drawings in which like reference characters designate corresponding parts throughoutthe several views and more particularly to Fig. 1 thereof, the numeral 10 generally designates the new and improved triboelectric generator comprising a hermetically sealed casing 11 composed of any material suitable for the purpose such, for example, as Bakelite, Lucite, or the like, and having a chamber 12 formed therein.

Disposed within the chamber 12 in engagement with the wall defining the chamber is a cup-shaped member or collecting cylinder 13 composed of any material suitable for the purpose such, for example, as copper and comprising a cylindrical wall 14, a bottom or connecting wall 15, and a flanged portion 16 adapted to collapse in response to impact of the projectile as the projectile strikes the target.

An inverted cup-shaped member or cylindrical grid generally indicated by the numeral 17 and composed of copper screen or the like foraminous material is disposed within chamber 12 and the member 13. The grid 17 comprises a cylindrical wall 18 in spaced concentric relation with respect to the wall 14 and a bottom or connection wall 19 secured to the casingas at 21 in any suitable manner and normally spaced from the flanged portion 16. it being noted that the end portion 22 of wall 18 is spaced from the wall 15.

Secured electrically to the walls 15 and 19 respectively in any suitable manner is a pair of terminals 23 and 24 thereby to provide external electrical connections for the members 13 and 17 the purpose of which will become more clearlyapparent as the description proceeds.

Disposed within the grid 17 and secured thereto as by a resilient ring 25 is a frangible container 26, the container having a quantity of powdered material 27 therein such, for example, as talcum powder. It will be understood, however that the container is composed of matesta Referring to the circuit arrangement of Fig. 2 it will noted that an electroresponsive detonator or primer andcondenserjiareconnectedin serieswiththe generator 1G by way suitable conductors connected to andflandthusitwillbeapparentthat the charged by the generator at a relatively slow through the detonator 28 in response to rotation of the projectile during the free flight of the projectile toward thetarget, being understood, however, that during this cycle.or-transferofenergy,therateisinsufdetonator 28 in an amount suflicient to fire the detonator therebyexplodingtheprojectile.

ThedeviceldofFig. 3isparticularlyadaptedforuse .inabssefuzeandissimilartothestructureshownon Fig. 1, except that thefiange 16 has been deleted from the coIlectingcylinderB'andinIieuther-eofaninertiareaponsive element generally indicated by the reference character 31 is employed in connection with an additional eontactelementiizinsulatedfromthewallflbyasleeve 33 composed of suitable insulating material.

11ieelement31comprisesapairofresilientarms34 aectuedelectr'icallytothe wall15ofmemberl3asat35, andextending-outwardly therefrom inopposite directions, thearmshaving weighted contact elements 36-37 formed thereon and normally out of engagement respectively with "an amount suficient to fire the detonator.

theterminalflandendportionuofthecylindrtcalwall 18 of grid 17. The arms 34 are adapted to be moved first-inonedirectionandthereafterinthereversedirectioninresponsetosetbackandsetforwardforcesre apectivelyaswillbehereinaftermorefullysetforth.

Referringnow to the circuit arrangement of Fig.- 4 for a more complete understanding of the operation of thebase-fuzeoffig.3itwillbenotedthatinthisarrangement the detonator 28 and condenser 29 are shorted when the element 36 moves into engagement with the terminal32inresponsetosetbackforceproducedas theprojectileisfiredfromsgunandwillremainshorted untilthesetbackforcehasdecr'easedsufiicientlytopermitthearms34tomovetotheirnormalposition. When this occurs and in response .to the rotation. of the projectileasheretoforesetforth,thecondenser29willbe charged. However, on impact of the projectile with the target the inertia responsive device is moved forwardly in response to the setforward force received thereby whereupon the elements 36-31 on arms 34 move into engagement with the member 17 shorting cylinders 13' and 17 and thus. the condenser 29 instantaneously discharges in In the arrangement of Fig. an additional grid member 38 is employed for producing a uniform distributionofthedustandtherebyinereasingtheoutputofthe generator'and comprises a conical grid member 39 se- I-lowever, upon impact of curedtothecasinginanysuitablemannerandextending i into a second grid member 41 which is substantially enclosed by a collecting cylinder 42 similar to the arrangements of Figs. 1 and 3. A frangible dust container or ball 43 composed of any material suitable for the purpose such, for example, as glass or the like is disposed at one end of the member 38 and is enclosed by a collapsible bellows 49. and thus when the bellows is collapsed in response to a sudden shock or pressure applied thereto in any suitable-manner as the projectile is tired from a gun, the ball is crushed thereby and the dust is releasedtherefrom. When this occurs and in response to the high speed of rotation of theprojectile, the particles of dust or p wder. be forc d t a loc y o e th a conical wall of member 38 and dispersed through the openings therein at a high rate of speed, it being understood, however, that some of the dust particles will travel upwardly along the conical wall of the member 38 and be dispersed at the upper open end thereof. The aforesaid particles thereafter are forced through grid 41 and collect on the cylindrical wall of member 42 whereupon a static charge is collected on grid 41 and cylinder 43. It will be noted in the arrangement of Fig. 5, a terminal 45 is secured to the element 41 and a terminal 46 is secured to the element 42 for providing an external electrical connection thereto, the device being adapted to function in the same manner as the device of Fig. 1 when the element 41 is forced into engagement with a flange 47 on element 42 upon impact of the projectile with a target.

Briefly stated in summary, the present invention provides I a fuse arrangement for a projectile comprising a tribeelectric generator hermetically sealed within a suitable casing adapted to function and produce electrical energy in response to rotation of the projectile during the free flight of the projectile along its trajectory whereupon a storage device is charged at a slot rate through an electro-responsive detonator, the rate at which the energy is transferred to the storage device being insuflicient to However, upon impact of'the profire the detonator. jectile with a target the storage device is instantaneously discharged through the detonator in an amount suficient to fire the detonator and thus causing the projectile to explode. The amount of the charge depends upon the speed of rotation of the projectile, the particle size of the dust and the number of dust particles forced through i the grid and the velocity at which the particles pass from the grid and collect on the outer cylinder.

Obviously many modifications and variations of the invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described. l

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

Whatisclaimedasnewanddesiredtobesecuredby I Letters Patent of the United States is:

1. In an electric fused projectile of the character disclosed, the combination of an energy storage device, an

electroresponsive detonator series coupled to said storage device, a triboelectric energy generating device series coupled to said detonator and storage device for slowlycharging said storage device through said detonator at' a rate insutficient to fire the detonator asthe generating device is rotated, said storage device being adapted'to quickly discharge the energy stored therein through the detonator at a rate suficient to fire the detonator in. re spouse to impact of the projectile with a target, and means on said generator for causing said discharge of the energy in response to said impact.

2. An electric fuze of the character disclosed for use in a projectile comprising, in combination, an energy storage device, an electroresponsive detonator, a generator connected in series with said detonator and storage device and actuated in response to rotation of said projectile, said generator including a grid for collecting an electrostatic charge thereby charging said storage device through said detonator at a rate insufiicient to fire the detonator as the generator is rotated, and impact responsive means on said generator in close spaced adjacency to said grid and electrically connected to said storage device for engaging said grid thereby causing discharge of said storage device through said detonator at a rate suificient to fire the detonator upon impact of the projectile with a target. v

3. In an electric fuze of the character disclosed foruse in a projectile, in combination, an energy storage device, an electroresponsive detonator, a hermetically sealed triboelectric generator connected in series with.

said detonator and storage device and comprising a grid member disposed within said generator, a quantity of dust, means for sealing said dust within said generator and for releasing the dust for passage through said grid member in response to centrifugal force as the projectile spins and means incluuding said grid member for generating electrical energy as the dust is forced therethrough in response to said force, circuit means for transferring said electrical energy to the storage device through said detonator at a rate insufficient to fire the detonator during rotation of the generatorand for discharging said energy from said storage device through said detonator at a rate sufficient to fire the detonator upon actuation of the circuit means in response to impact of the projectile with a target, and means responsive to said impact for actuating said circuit means and causing the energy to be discharged from said storage device.

4. In an electric fuze of the character disclosed for use in a projectile, comprising, in combination, a casing, a condenser, an electroresponsive detonator, a generator hermetically sealed within the casing, a grid member disposed within said casing, a frangible container disposed within said grid and secured thereto, a quantity of powder disposed within said frangible container and released therefrom through said grid as the frangible container is ruptured in response to centrifugal force, means including said grid member for generating electrical energy as the powder is forced therethrough into engagement with said last named means in response to said force, circuit means for transferring said energy to the condenser through the detonator at a rate insufficient to fire the detonator during rotation of the generator and for discharging the energy from the condenser through the detonator at a rate sufficient to'fire the detonator when the circuit means is actuated in response to the impact of the projectile with a target, and means on said generator for actuating said circuit means and causing the energy to be discharged from the condenser in response to said impact.

5. In an electric fuze of the character disclosed for use in a projectile, comprising, in combination, a hermetically sealed casing, a condenser, an electroresponsive detonator, a generator disposed within the casing and comprising an outer cylindrical member and an innet cylindrical grid member disposed within and substantially enclosed by said outer member, a frangible container disposed within said grid member and secured thereto, a quantity of powder disposed within said con tainer and released therefrom as the container is ruptured in response to centrifugal force applied thereto, said grid ing rotation of the generator and for discharging the energy from the condenser through the detonator at a rate sufiicient to fire the detonator as the outer member is forcibly driven into engagement with said inner member in response to impact of the projectile with a target.

6. An electric fuze of the character disclosed for use in a projectile and comprising a condenser, a triboelectric generator comprising a frangible container having a quantity of powder therein and rupturing in response to rotation of the projectile during flight for charging said condenser, an electroresponsive detonator, and circuit means comprising a path for discharging said condenser through the detonator at a rate sufiicient to fire the detonator as the projectile strikes a target.

member and outer cylindrical member being adapted 7. An electric fuze-of the character disclosed for use in a projectile comprising a casing, a generator hermetically sealed within said casing and having inner and outer cylindrical members secured thereto, said inner member having a plurality of apertures formed therein, a frangible container disposed within and secured to said inner container, a quantity of powder disposed within said container and released therefrom as the container is ruptured in response to centrifugal force applied thereto for charging said inner and outer cylindrical members with electrical energy as the powder is forced through said apertures and collected on the outer cylindrical member in response to rotation of the generator, and. an eiectrorc sponsive detonator and a condenser connected in a series circuit with the generator, said generator charging said condenser through said detonator at a rate insufficient to fire said detonator, said circuit comprising a discharge path from the condenser and including said inner and outer members for discharging said condenser through the detonator at a rate sufficient to fire the detonator as the outer cylindrical member is driven into engagement with said inner cylindrical member in response to impact of the projectile with a target.

8. A triboelectric generator comprising a hermetically sealed casing, a cylindrical member disposed within an: secured to said casing, a pair of perforated cylinders disposed within said cylindrical member in coaxial spaced relation with respect thereto and with respect to each other, a frangible container disposed within the inner one of said cylinders, pressure responsive means enclosing said container for fracturing the container as said pressure responsive means is forcibly driven into engagement therewith in response to a sudden shock received thereby, a quantity of powder arranged with the com tainer and released therefrom as the container is fractured thegeby charging one of said perforated cylinders and the cylindrical member with a static charge as the powder is forced through said pair of perforated cylinders and collected on the cylindrical member in response to rotation of the generator.

9. In a projectile or the like, a device for generating electrical energy in response to rotation thereof comprising a hermetically sealed casing, a cylindrical member disposed within and secured to said casing, a cylindrical grid disposed within and spaced from said cylindrical member, a frangible container arranged within and secured to said grid, a quantity of powder disposed within said container and released therefrom as the container is ruptured by the force applied thereto in response to firing of said projectile, whereby electrical energy is generated between said cylindrical member and grid as the powder is forcibly ejected outwardlythrough the grid and callected on the cylindrical member in response to rotation of said projectile.

References Cited in the tile of this patent UNITED STATES PATENTS 

